And, no one said they did
I'm one of the two posters who commented about gender reveal parties. Neither of us implied in ANY way that anyone is offended by or has a "problem with" these parties. We just both said that we PERSONALLY aren't fans of them and don't really see the point.
That said, you (and a few others on this thread) seem to be implying that there is one unified ideology that is "LGBT" that all who fall under that heading would agree upon. Almost like a specific religion where there are beliefs that are agreed upon and held in common by it's members. That is far from the reality. It's more like the general heading "Religion" where there are many different religions within that have completely different beliefs, lifestyles, etc.
And just like with Christianity, Islam, etc., these little religions don't agree on everything or even necessarily like each other. Gay men and lesbians tend to be fairly vocal about hating each other. Demographic studies of the US show that they generally don't even live in the same areas because they share little in common. The Michigan Womyn's Music Festival (a lesbian safe-haven) was shut down a few years ago over the controversy that they would only allow people "born in female bodies" (banning trans women from attending). So, there's definitely not one unified "LGBT" position on gender identity.
This is absolutely an issue. My oldest was part of the trans community for several years and eventually realized how stifling it was for her. There was a strong pressure to "pick a label" and stick with it. There was a tremendous focus on what's "masculine" and "feminine" and when she started to question some of this she would be strongly attacked and threatened online and even among some of her friends at college. The belief was that she wasn't being "tolerant", but really she was just questioning the labels and why certain things were considered to be exclusive of one gender or the other. (Does one really have to become a man just because one doesn't 100% fit the mold for a woman or vice versa?)
Sexuality also plays a role into all of this. There are some subsets of people (among both trans and cisgender) who uphold the normal/natural nature of heterosexuality so strongly that they believe if you are attracted to someone of the same gender, that you must be wrong. i.e. If you're a female attracted to women, you're really supposed to be a male. So for some there's a pressure to transition in order to have their relationships accepted as a more traditional male/female coupling rather than being seen as gay or lesbian.
*Note... I'm not referring to
everyone who is trans in the above, just specific people/groups whose beliefs are very rigid. Even if they're not the majority, they still can have an impact on some young people who are trying to navigate questions of their sexuality and identity.